The present invention relates to a getter assembly with an improved support to avoid high temperatures at the points of contact of the supports with the wall of the electron tube in which the getter device is located.
It is known that getter devices are widely used in tubes for the representation of visual images such as cathode ray tubes. In use the getter assembly is heated to a high temperature usually by means of high frequency induction, so that a gettering metal, normally barium, is caused to evaporate from the getter assembly. This can be located within the cathode ray tube in the "antenna" position or attached to the anode button but, whatever its position it is usually in usually in contact with the internal surface of the glass envelope of the cathode ray tube.
Unfortunately the high temperatures, even greater than 1000.degree. C., reached by the getter device during evaporation of the gettring metal are such as to provoke rupture of the glass envelope. It has therefore become the normal practice to provide some tyoe of the thermal insualtion or support between the getter material container and the glass wall. Ceramic insulators have been used as described in U.S. Pat. No. 3,381,805 or metal wire supports as described in U.S. Pat. No. 4,101,247. Another type of support is described in Japanese Utility Model Publication No. 50-11453.
Unfortunately such insulating means or supports are costly or still have too high a temperature at the point of contact between the support and the glass envelope, especially when the getter device has a small diameter.